Origin of Doppelganger Chess: Many years ago I saw a Twilight Zone
episode about a lady who was waiting at a desolate bus station. In the dim light
and silence she eventually got a glimpse of someone someone who looked just
like her and who was there to take her place in the world she had seen her
doppelganger. On the morning of May 1st, 2004 I awoke with
Doppelganger Chess in my head. It is based on the presence of Doppelgangers
(shadow walkers). Doppelgangers are indistinguishable from normal earthly chess
pieces.

How to play: Standard 8x8 board western chess setup and movement apply,
with the exception of what happens after a piece is captured and what happens
after a pawn is promoted. The object is to checkmate your opponent.

Captures: The captures are based on the existence of Doppelgangers. The
person making the capture removes the captured piece and its counterpart (a
Doppelganger). Thus, if a Bishop is captured both enemy Bishops are removed from
the board. If a pawn is captured, the player making the capture removes it plus
any oneother enemy pawn (capturers choice). If the
removal of the second piece (or pawn) causes check to your opponent, that is
fine. But you cannot capture a piece (or pawn) if removal of its counter part
would put your King in check. Queens have no Doppelganger, so capturing a Queen
results in only in removal of that Queen.

Promotions: A pawn promotion is always a Doppelganger Promotion
and must result in adding 2 Rooks, 2 Knights, or 2 Bishops. You can end up with
4 rooks, 6 rooks, etc. You cannot promote a pawn to a Queen. To promote a
pawn: (1) move it to the last rank, (2) replace it with a Bishop, Knight, or
Rook, (3) remove one of your other pawns (4) replace it with the second Bishop,
Knight, or Rook. If either piece is captured now (or later) both it and its
counterpart are removed. Note: You can end up with two light or two dark-squared
Bishops as a result of promotion, depending on where the second pawn is.

A Note in Closing: In the original game (the one that I awoke with) black
pieces were doppelgangers relative to white pieces and visa versa. When you
captured a piece both it and a matching one of yours was removed. Even
promotions resulted in a promotion for your opponent. Material balance was
maintained throughout the game, and it was very difficult to achieve victory.
That game is a real workout and can be very frustrating. I changed the game so
that each side had its own doppelgangers and by doing so created great
opportunity for dynamic imbalance. Based on games played, the game submitted
here is much more fun than the subconsciously created version, but should there
be any interest in the original game, I will gladly submit the rules.

Comments

Hello Abdul: I went to edit the page, but I see it is one that I don't have editing privileges for. So I will contact Jeremy in regard to an update. In the mean time, if you wanted to make a Zillions program of the newer variant, I'd have no objections. Regards, Gary

Abdul-Rahman Sibahi, Thank you for commenting. Your idea would certainly work and I did think about it back when the game first appeared. The way I imagined it was simple, accomplished by linking pawns: K and Q pawns, both B Pawns, both Knight Pawns, both Rook Pawns... each a Doppelganger to their 'linked' associate. Since Pawns change files from time to time, they would need an identifier to show Doppelganger relations.
I prefer the idea of more player control which exists in the current version. Note - the Doppelganger Pawns are 'not random' ... the rules state:
'If a pawn is captured, the player making the capture removes it plus any one other enemy pawn (capturer’s choice). If the removal of the second piece (or pawn) causes check to your opponent, that is fine. But you cannot capture a piece (or pawn) if removal of its counter part would put your King in check.'
As to which is the better concept (pre-determined Pawn-doppelganger or Player-selected Pawn Doppelganger), that probably is a matter of opinion, like comparing Chinese Chess and Korean Chess. On that call, I am in the minority.
Your idea is certainly logical, has merit, and would prove easier for programmers. I sort of like coming across games that computers do not yet play... but usually it is only a matter of time before they do.
I seem to recall seeing a set of pieces with different colors at the bases. Pawns of that design would work with your suggestion.
If you want-I will add the variant to Doppelganger and call it something like 'the Abdul-Rahman Sibahi Doppelganger Variant' and give you credit. You could modify the pawn Doppelganger aspect if desired, based on proximity. There are several different pawn-link possibilities. Just let me know. Or, if you'd like to create a separate page with your rules - as your variant of Doppelganger - I have no problem with that. It would need its own pre-set to keep the ratings aspect fair.
Thanks again, very much, for the comment. Best regards, Gary

Abdul-Rahman Sibahi, Thank you for commenting. Your idea would certainly work and I did think about it back when the game first appeared. The way I imagined it was simple, accomplished by linking pawns: K and Q pawns, both B Pawns, both Knight Pawns, both Rook Pawns... each a Doppelganger to their 'linked' associate. Since Pawns change files from time to time, they would need an identifier to show Doppelganger relations.
I prefer the idea of more player control which exists in the current version. As to which is the better concept? That probably is a matter of opinion, like comparing Chinese Chess and Korean Chess. On that call, I am in the minority.
Your idea is certainly logical, has merit, and would prove easier for programmers. I sort of like coming across games that computers do not yet play... but usually it is only a matter of time before they do.
I seem to recall seeing a set of pieces with different colors at the bases. Pawns of that design would work with your suggestion.
If you want-I will add the variant to Doppelganger and call it something like 'the Abdul-Rahman Sibahi Doppelganger Variant' and give you credit. You could modify the pawn Doppelganger aspect if desired, based on proximity. There are several different pawn-link possibilities. Just let me know. Or, if you'd like to create a separate page with your rules - as your variant of Doppelganger - I have no problem with that. It would need its own pre-set to keep the ratings aspect fair.
Thanks again, very much, for the comment. Best regards, Gary

If the removal of the doppleganger pawn was automatic, (not random,) like choosing the closest piece to the captured piece or choosing the closest to the left hand corner, the game wouldn't necessarily be better, but it would be easier to implement in a chess program or a chess server (you have only to make the move, and the program will take care of the rest.)
Just a thought...
I should try this game someday.